AS/NZS 3000:2018 Amendment 2: Changes to Wiring Rules You May Have Missed

Amendment 2 responds to field experience since the 2018 edition. Most of these changes address scenarios that did not exist at scale when the base document was drafted.

Switchboard requirements — Clause 2.7

• Arc fault containment. Updated requirements for switchboard internal arc ratings in specific installation types (public buildings, healthcare facilities). This aligns with the trend in AS/NZS 61439.1 for type-tested assemblies with defined arc fault withstand.
• Labelling for embedded generation. Switchboards connected to solar PV, battery storage, or other embedded generation sources must now display specific warning labels identifying all sources of supply — not just the utility connection. This requirement directly addresses firefighter safety and isolation procedures.
• Spare capacity provisions. For new domestic switchboards, Amendment 2 recommends (not mandates) a minimum of 20% spare circuit capacity to accommodate future EV charger and battery system additions without consumer unit replacement.

Circuit protection — Clause 2.5.4

• Clarified requirements for protection device discrimination in installations with multiple sources (grid + solar PV + battery inverter)
• Updated provisions for DC circuit protection in prosumer installations, referencing AS/NZS 5033 for PV array circuits and the new battery storage provisions
• Explicit requirement that protection coordination studies be documented for commercial and industrial installations with embedded generation

EV charging installations — Section 4.16

AS/NZS 3000:2018 Amendment 2, Section 4.16 introduces specific provisions for EV charging that were previously covered only by general socket-outlet and fixed appliance requirements:

• Dedicated circuit required for each EV charger — no sharing with other loads on the same final circuit
• Type A RCD minimum for Mode 2 (portable charger) and Mode 3 (wall box) single-phase connections. Type B or equivalent DC-sensitive RCD required where the charger does not incorporate internal DC fault detection per the manufacturer’s installation instructions
• Cable sizing at 100% continuous load rating — a 32 A charger requires a cable rated for 32 A continuous, with no diversity applied to the individual circuit. This catches the common error of sizing an EV circuit like a socket-outlet circuit with assumed diversity
• Supply conductor sizing must account for voltage drop at full rated current over the actual cable length, which for detached garages and carports can be 25–40 m

RCD requirements — Clause 2.6.3

Amendment 2 extends RCD requirements to additional circuit types:

• All outdoor lighting circuits now require RCD protection (30 mA), closing a gap where some outdoor lighting was previously exempt if permanently wired
• Circuits supplying equipment in garages and carports require 30 mA RCD protection, regardless of whether socket-outlets are present

Maximum demand — Appendix C

The maximum demand calculation methodology in Appendix C has been updated to include:

• EV charger contribution: 100% of rated current for the first charger, 50% for the second, 30% for subsequent chargers in a domestic installation with load management
• Battery storage system contribution: the maximum inverter output current, regardless of battery state of charge, because the inverter can deliver rated current from either the battery or pass-through from PV
• Updated diversity factors for residential developments with high EV adoption, relevant for feeder and transformer sizing in new subdivisions

Standards referenced: AS/NZS 3000:2018 Amendment 2, AS/NZS 3008.1.1:2017, AS/NZS 5033:2021, AS/NZS 61439.1.

Amendment 2 is normative from its publication date. For projects in progress:

1. Check your project’s compliance baseline. If your design was submitted for approval before Amendment 2’s effective date, you may complete the installation under the previous requirements. New submissions after the effective date must comply with Amendment 2.
2. Review EV charging designs immediately. The 100% continuous load requirement and dedicated circuit provisions are the most common non-compliance issues in current designs. A 7 kW single-phase EV charger at 32 A continuous over a 30 m run may require a larger cable than your standard template specifies.
3. Update maximum demand calculations. If your project includes EV chargers or battery storage, recalculate maximum demand using the updated Appendix C methodology. This may affect upstream cable, switchboard, and transformer sizing.
4. Audit RCD schedules. Check that outdoor lighting and garage circuits have 30 mA RCD protection specified. This is a simple addition but one that inspection authorities will enforce immediately.